This invention concerns construction site light marking devices in which the marking lamps are arranged in series along a looped circuit and specifically concerns an energy-saving light marking device with low power consumption.
There are three types of light marking devices used for identifying work being performed at airports, and more particularly on taxiways.
The first type of lighting system is a standalone device featuring a certain number of individual lights powered by storage batteries generally placed on a metallic support based. Although compact type fluorescent sources are used (generally, a 5 W fluorescent bulb), thus consuming little energy while providing minimum lighting with low power consumption, this device has an autonomy of approximately 12 hours. In order to offset this major drawback, the equipment which makes up this lighting device is generally doubled in order to always have one set of lights being recharged, and one being used. In addition, in order to ensure reliable installation on the tarmac, this device is generally completed by a system of heavy and stable metal bases. These two drawbacks thus make this standalone device poorly adapted to semi-permanent installations ( greater than 3 days). An installation of this type requires frequent changing operations and results in high acquisition and battery maintenance costs.
The second type of lighting system features a certain number of 220VAC lights, interconnected by extension cords. The lights are almost always fabricated by the airport""s technical department itself and consist of traditional xe2x80x9cabove-groundxe2x80x9d lights, whose internal marking light type lamp base has been replaced by a standard screw or bayonet-type socket for a 40 or 60 W bulb. The socket is connected to a male connector and a 220 V female plug, generally watertight, designed to be connected to the extension cords. The assembly is secured to a metal base which provides support. Such a device presents a certain number of drawbacks. Firstly, its installation requires very long 220 V extension cords made using commercially-available hardware (1.5 to 2.5 mm2 cable with ground, rubber watertight connectors and sockets) as this device often must deal with the lack of power sources (220V) available near the location where the light marking is to be done. In addition, the service life of the majority of these extension cords is short due to the passage of miscellaneous vehicles. These drawbacks make this device costly and unreliable.
The third type of light marking offsets the drawbacks of the previous devices by using an existing lighting loop, such as a runway lighting loop at an airport, for example. It consists in adding an additional current transformer in the lighting system""s primary circuit, meant to be used as the head transformer. This light marking device consists of 30 to 65 W standard marking lamps (halogen or filament lamps), and thus requires a head transformer of approximately 500 W for roughly ten lamps. The wiring is generally made on site, for occasional needs, and the series connection of the lamps requires that numerous watertight junctions be made. Wiring such a device generally requires that a loop be xe2x80x9ccustom madexe2x80x9d. The last type of lighting, derived from and similar to the third type described above, consists in using a head transformer, the primary winding of which is powered by an alternating current source and whose secondary winding powers a plurality of current transformers. A lamp is connected to each secondary winding of all the transformers and all the primary windings of all the transformers are connected in series to the secondary winding of the head transformer. The major drawback of this type of lighting device connected in series is that it requires a substantial power increase from the existing loops to which it is connected. The use of fluorescent lamps instead of incandescent or halogen lamps reduces the amount of current required by the system although requires a high voltage value at the lamp terminals to start them, generated by a lamp starter. The latter consists primarily of a starter and a ballast. The starter is used to start the system, i.e. heating two electrodes located at the ends of the lamp, and the ballast creates an initial surge voltage which allows the flow of electrons to move through the lamp, which is generally tubular in shape. Once started, the voltage required at the terminals of the fluorescent lamp is lower.
This is why an initial purpose of the invention is to provide a lighting device using fluorescent lamps that do not require lamp starters.
A second purpose of the invention is to provide a lighting device that requires only a small amount of power while providing satisfactory light intensity.
Another purpose of the invention is to provide a temporary light marking device which can be inserted into an existing runway lighting loop without an excessive increase in power.
The purpose of the invention is thus an energy-saving light marking device with low power consumption including a head transformer, the primary winding of which is supplied by an alternating current source and a plurality of marking lamps in series connected to the terminals of the secondary winding of the head transformer, each of the marking lamps being comprised of a fluorescent lamp powered by the secondary winding of a secondary transformer, the primary windings of all the secondary transformers of the marking lamps being connected in series between the terminals of the head transformer""s secondary winding. According to the main characteristic of the invention, each of the fluorescent lamps is started by the voltage surge generated at the terminals of the secondary winding of the secondary transformers when the primary winding of the secondary transformers is energized while the lamps are not yet started.